Isotopenola loftyensis ( Womersley, 1934 )

Potapov, Mikhail, Babenko, Anatoly, Fjellberg, Arne & Greenslade, Penelope, 2009, Taxonomy of the Proisotoma complex. II. A revision of the genus Subisotoma and a description of Isotopenola gen. nov. (Collembola: Isotomidae), Zootaxa 2314, pp. 1-40 : 33

Isotopenola loftyensis ( Womersley, 1934)

Figs 11 , 97–105

Cryptopygus loftyensis Womersley, 1934: 88

Proisotoma (Subisotoma) loftyensis ( Womersley, 1934) : Greenslade 1994

Material. Lectotype (designation by Greenslade (1994)), Mt Osmond, South Australia. 4 individuals, South Australia, Mt Lofty Ranges, Belair Nat.Park, near second waterfall on creek, 14.vii.1973, under bark of Eucalyptus , leg. P. Greenslade ( SAMA); 2 individuals, South Australia, Mt Lofty Ranges, Glen Osmond, leg. P. Greenslade (546) ( SAMA)

Redescription. Size 1.1–1.6 mm. Colour unknown in our specimens (entirely blue from first description). Body plump, with cryptopygy. Cuticle with pits regularly scattered all over body, larger on head ( Fig. 97 ). A part of corpus and head with secondary granulation. All 8+8 ocelli, G and H smaller and hardly visible. PAO wide elliptic, without constriction, 1.6–1.8 as long as ocellus diameter and 0.8–1.0 as long as U3. Maxillary palp simple, 4 sublobal chaetae present. Labrum with 2/554 chaetae. Labium with all papillae A–E present, papilla E with 4 guard chaetae, proximal chaetae 3. Basomedial field of labium with 4 chaetae. Ventral side of head with 4–6+4–6 postlabial chaetae along ventral line. Ant.1 with about 19 common chaetae, 2 bms (dorsal and ventral) and 2 ventral sensilla (s) ( Figs 98, 99 ), Ant.2 with 3 bms and 1 distal s, Ant.3 without bms and with 5 distal s, including one lateral in АО. Inner sensilla of АО clearly broadened, as long as outer ones, additional sensilla absent. Ant.4 with numerous poorly differentiated sensilla, subapical organite small, microsensillum present.

All terga with dense cover of uniform chaetae ( Fig. 97 ). Macrochaetae not differentiated. Dorsal axial chaetom of Th.II–Abd.III as 10–11,8–10/7–9,7–8,7–8. Tergal sensilla distinctly differ from ordinary chaetae, short and slender, uniformly distributed on the terga. With numerous sensilla on terga. The total number of sensilla not stable (13,10/7,8,10,15,16 in one specimen studied by us in detail, Figs 11 , 97 ). The number of tergal microsensilla 11/111. Sterna of Th.III without chaetae.

Unguis with clear inner tooth. Ti.1–3 with many additional proximal chaetae, the total number 27–30 on Ti.1 and more than 30 (up to 40) on each Ti.2 and 3 ( Figs 100–102 ). Tibiotarsal tenent chaetae 1–2–2, clavate, longer than inner edge of unguis (U3: t.ch. = 0.7). Ventral tube with 4+4 lateral and about 8 posterior chaetae (only one specimen checked). Tenaculum with 4+4 teeth and one chaeta. Submedial setaceous fields on Abd.III sterna with 5–10 chaetae, anterior furcal subcoxae with 12–16 chaetae, posterior ones with 11–13. Manubrium without anterior chaetae, posterior face with about 27 chaetae centrally and 4+4 laterobasal lobes (only one specimen checked). Dens with one anterior and 5–6 posterior chaetae. Mucro long, with 2 teeth, more or less clearly set off from dens ( Figs 103–105 ). Ratio of manubrium: dens: mucro = 4.5–5.1: 3.1–4.1: 1.

Affinity. This second Australian species of Cryptopygus described by Womersley undoubtedly belongs to Isotopenola . The presence of numerous sensilla on body, no needle-like but normal chaetae, more chaetae on postlabial area, tibiotarsi, antennae and other features distinguish I. loftyensis from I. australis . More abundant clothing of chaetae in loftyensis than in australis was also mentioned by Womersley in first description. Our redefinition of this species is based on lectotype from South Australia (Mount Osmond) and several specimens collected by P.Greenslade close by. The most important characters, as chaetotaxy of Ant.I and dens, approximate number of sensilla on body, were possible to see in lectotype.

We have also several undescribed forms/species from several localities in Australian Capital Territory, Victoria, South Australia (all leg. P. Greenslade) and New Hebrides (leg L. Deharveng & A. Bedos) sharing many characters with I. loftyensis which differ in number of tergal sensilla, chaetae on appendages, sensilla on Ant. I, e-guard chaetae on labium and other features. Taxonomical relations of these forms calls for further special study.

Distribution. Currently known only from South Australia.

Figures

FIGURES 9 – 12. Sensillar chaetotaxy of Isotopenola: 9, Isotopenola australis (5,5 / 4,4,4,4,5); 10, Isotopenola delicata sp. nov. (sensillar polychaetosis); 11, Isotopenola loftyensis (sensillar polychaetosis); 12, Isotopenola nilgiris (4,4 / 3,3,3,3,4).

FIGURES 97 – 105. Isotopenola loftyensis: 97, Th. II; 98 – 99, Ant. I, ventral (98) and dorsal (99) views; 100 – 102, chaetotaxy of tibiotarsi of legs 3 (100), 2 (101), and 1 (102); 103 – 105, mucro and dens, variability, 99, 103, lectotype.